Electronic ballast



FIG. 1 is a right, front perspective view of an electronic ballast showing our new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a side elevation view thereof, the opposite side being a mirror image;

FIG. 4 is a front view thereof; and,

FIG. 5 is a rear view thereof.

The broken line showing of an electronic ballast represents unclaimed subject matter and forms no part of the claimed design. 

CLAIM The ornamental design for an electronic ballast, as shown and described. 